GaN films are used in blue electroluminescent diodes and in generating blue laser. There have been reported studies to prepare such films by metal organic chemical vapor deposition (MOCVD) using such organogallium compounds as triethylgallium.amine adduct, bis(dialkyl-.mu.-amido-gallium), bis[dimethyl(1,1-dimethylhydrazido)gallium] and the like (see J. E. Andrews and M. A. Littlejohn, J. Electrochem. Soc., 122, 1273 (1975); U.S. Pat. No. 4,975,299 and European Patent Application 0 295 467 A2; and V. Lakhotia, D. A. Neumayer, A. H. Cowley, R. A. Jones and J. G. Ekerdt, Chem. Mater., 7,546 (1995)).
However, as these GaN precursors exist in the form of dimers or trimers, which are often solids at room temperature, they are difficult to handle in MOCVD due mainly to their low vapor pressures. Further, these conventional precursors are known to give GaN films which have lattice nitrogen defects.
The present inventors have endeavored to develop a novel compound which can be employed in an improved MOCVD process for preparing a GaN film of improved quality, and have discovered that an azidodialkylgallium.hydrazine adduct has high volatility and can be effectively used in MOCVD to form a GaN film having no significant amount of nitrogen defects.